Sydney hit by dust storm again

Wild winds whipped up dust storms across Queensland and New South Wales, Australia's most populous state, overnight, bringing fresh clouds of grit from thousands of kilometres away, the weather bureau said.

Satellite pictures showed a band of dust about 200 kilometres (125 miles) wide, sweeping from central Australia towards the east coast, with visibility in Sydney limited to five kilometres, said forecaster Barry Hanstrum.

"We've got an area of widespread dust but not as thick as it was on Wednesday," said Hanstrum, referring to the freak red storm that choked Sydney earlier this week.

"It's likely to clear through the metropolitan area through mid-morning."

Millions of tons of dust smothered north-eastern Australia in a rust-red dawn Wednesday which ground air and harbour transport to a halt and left hundreds of people hospitalised with breathing problems.